WILLEMSTAD – Attempts to restore Curaçao's electricity system after the August 27, 2025 blackout failed seven times before the grid was successfully brought back during the eighth attempt, exposing weaknesses in restoration procedures and reactive-power management.
An independent review by ENGIE/Laborelec for the Regulatory Authority of Curaçao says the experience demonstrates the need for clearer restoration procedures, alternative strategies and a formal role for Aqualectra's new Battery Energy Storage System during future blackouts.
For the first time, the restoration process following a Curaçao blackout was subjected to a dedicated technical analysis. The move followed a recommendation made in 2024.
One of the problems identified occurred at Dokweg, where an uninterruptible power supply, or UPS, was expected to provide backup electricity for approximately eight hours.
Instead, it lasted less than one hour.
Aqualectra informed the investigators that the problem was corrected after the blackout and that its UPS systems are tested annually. Laborelec nevertheless stressed the importance of regular testing, particularly because high temperatures can significantly reduce the lifespan of such equipment.
An even more significant problem emerged during attempts to re-energize the electricity network.
According to the report, the amount of reactive power that had to be absorbed was too high during each of the first seven restoration attempts. During the eighth attempt, which succeeded, that amount was substantially lower.
Laborelec says this likely points to a lack of sufficiently formalized procedures and alternative restoration routes for situations in which the preferred route cannot be successfully re-energized.
The report recommends developing and formalizing a new restoration sequence that incorporates the BESS battery plant.
Using BESS during the early stages of restoration could help stabilize generating units while simultaneously supporting voltage and frequency. The investigators believe this could make future recovery from a major blackout considerably faster.
The report also calls for additional simulations so operators know beforehand how much reactive power must be managed during each stage of restoring the network. DNV has already been appointed by Aqualectra to further investigate reactive-power behavior during restoration.
The findings are particularly relevant because restoring electricity after a total system collapse is different from simply starting generating units. The network must be rebuilt in a controlled sequence while operators maintain a delicate balance between generation, voltage, frequency and reactive power.
Laborelec says the 2025 blackout and restoration process revealed remaining weaknesses despite the substantial progress Aqualectra has made in recent years.
The regulator is therefore advised to continue monitoring not only the technical upgrades to Curaçao's electricity system but also whether formal procedures are established and consistently applied for critical operations.
According to the review, better procedures, improved reactive-power planning and support from BESS should allow Curaçao to recover more quickly if another major system failure occurs.